Matthew 21

1 The exact location of Bethphage is unknown, but appears to have been located on the Mount of Olives. Mark 11:1 places Bethphage between Bethany and Jerusalem. It would have been less than two miles east of Jerusalem. The Mount of Olives was about 200 feet higher than Jerusalem, and would have given a good view of the city and the Temple.
2 Jesus used divine knowledge to describe where the colt He was to ride was located. The disciples were to bring it quickly.

Matthew mentions both the mother donkey and her colt. While the other three gospels only mentioned the colt, it is likely that the mother was also brought along for the colt's sake.

3 The disciples were not to waste time asking permission first. The owner would find them and ask them, but then immediately release the colt (and the donkey) into their custody.
4 Again, this was to fulfil another significant prophecy. This one is found in Zec 9:9.
5 Most kings would enter a city on a horse with a show of power and splendor. The Messiah would enter Jerusalem humbly on a donkey. This is picture also draws a parallel between Jesus and King David (1 Ki 1:33). His kingdom would be built by people freely submitting to Him, not by conquest or oppression.
7 This is the only time we see Jesus riding an animal. It is appropriate because Jesus was entering Jerusalem as their King.

Kings typically would dress their horses with brightly colored cloths. The disciples did not have any of this, so they used their outer garments (coats) as regiment and cushioning.

8 Many people were camped around the road to Jerusalem as they prepared to celebrate the Passover. Jesus' reputation as a prophet and miracle worker proceeded Him, and many people thought He might be heading to Jerusalem to set up a new kingdom. This kingly parade was not something the crowd expected. An earthly king might expect that his pathway to a city be covered in fine fabric and flower petals (i.e., the "red carpet treatment"). The people did not have any of that, so clothing and palm leaves served to honor Jesus as He approached the city.
9 "Hosanna" means, "please save." While originally a cry for help, it had also become a word of acclamation (Psa 118:25). The second phrase used comes from Psa 118:26, and was sung during the Passover. The people were calling Him the Son of David which indicated that they recognized His right to the throne and His position as Messiah. It is likely that most of the people were expecting political "salvation" from Roman rule. They did not understand the spiritual implication of their words that would lead to a more significant salvation from the punishment of sin.
10 The people outside the city made a lot of noise. Since the people inside the city had not expected anyone of great importance to arrive, they were asking what the commotion was. Certainly, the Jews would not honor a visiting Roman official. Who then was this whom all the people were honoring?
11 Jesus had been to Jerusalem several times and had visited many of the other towns from which people came. He was widely known as a prophet and miracle worker.
12 Jesus cleared the merchants from the Temple at the beginning of his ministry (John 2:14-16), and does so again at the end. Neither the priests nor the merchants had taken note of what Jesus had tried to teach them about respecting the purpose of the Temple.
13 It was to be a place where one could pray and worship, not be bothered by the commercialization of the world. It was also hypocritical for merchants to use the courtyards of the Temple to "assist" worshipers on one hand while charging them unfairly high prices for this "service." The focus was on money, not God, and that was reprehensible. It is most likely that this merchandizing occurred in the court of the Gentiles, and thus interfered with the worship of non-Jewish believers. Jesus quotes from Isa 56:7 and Jer 7:11.
14 Jesus' entry into the city made quite a stir, so most people knew He was at the Temple. The stories about His miracle had spread everywhere, and anyone who had an ailment went to Him.
15 Jesus did many miracles, and even the children were shouting messianic attributes about Him. The religious leaders saw Jesus as a normal man and were upset that an ordinary man would allow people to call Him the Messiah. They thought that if Jesus were even a "good" or humble man that He would have the decency to stop such praises.
16 What was difficult for the religious leaders to understand was intuitively obvious to the children. The children's praise was "perfect" because they did so without any hesitation or hidden agenda. Jesus is good and humble, but He is also the Messiah. He deserved to be praised as such.
17 Jesus did not spend the nights in Jerusalem. If He had relatives living there then it would have been appropriate for Him to lodge with them. The many followers He had either did not have homes in Jerusalem, or were occupied with their own family matters and did not invite Him into their homes. Another reason not to stay was to prevent the religious leaders from setting up a murderous ambush against Him at night. Apparently, the two-mile distance to Bethany was enough to prevent this from happening until the right time.
23 After Jesus cleared the Temple the first time, the Jews had asked Him the same question (John 2:18). The merchants that Jesus had cleared from the Temple had been there with the full approval of the religious leadership. Who was Jesus, then, to drive them out? Did He have more authority than the priests of God did?
25 The answer to Jesus' question would answer their question. John the Baptist was a prophet who, by God's Spirit, had indicated that Jesus was the Son of God (John 1:34). If they recognized John's message was from heaven then they would have to admit that Jesus was the Son of God, and obviously had more authority than the priests had.
26 What held them back was their fear of the crowds. The common people would have considered it blasphemy to say that John the Baptist was not a prophet. They might have risen up and stoned the religious leaders for saying such things, even if they were formally respected.
27 The religious leaders came up with an answer that neither acknowledged John as a prophet nor denied it. However, such a response did indicate that they did not believe John was a prophet. They had not responded to John's message when He gave it, and they did not want to believe it after his words came true.

It was obvious that the religious leaders would not believe Jesus if He told them where His authority came from, so He did not tell them directly. Instead, He told parables to illustrate where His authority came from.